Back to EveryPatent.com
United States Patent | 5,301,205 |
Tsutsui ,   et al. | April 5, 1994 |
A data compression apparatus for compressing a digital input signal to provide a compressed digital output signal. In the apparatus, a circuit derives plural spectral coefficients from the digital input signal, and groups the spectral coefficients into bands. An adaptive bit allocation circuit adaptively allocates a number of spectrum-dependent quantizing bits among the bands to allocate to each band a number of spectrum-dependent quantizing bits for quantizing each of the spectral coefficients in the band. The number of spectrum-dependent quantizing bits allocated to each band by the adaptive bit allocation circuit is determined according to the band magnitude, weighted depending on the band frequency.
Inventors: | Tsutsui; Kyoya (Kanagawa, JP); Akagiri; Kenzo (Kanagawa, JP) |
Assignee: | Sony Corporation (Tokyo, JP) |
Appl. No.: | 011376 |
Filed: | January 29, 1993 |
Jan 29, 1992[JP] | 4-036952 |
Current U.S. Class: | 375/340; 380/46; 704/200.1; 704/203; 704/205; 704/229 |
Intern'l Class: | H04K 001/00 |
Field of Search: | 375/1 380/46 |
4184049 | Jan., 1980 | Crochiere et al. | 381/31. |
4455649 | Jun., 1984 | Esteban et al. | 381/31. |
4535472 | Aug., 1985 | Tomeik | 381/31. |
4870685 | Sep., 1989 | Kadokawa et al. | 381/31. |
4885790 | Dec., 1989 | McAulay et al. | 381/36. |
4896362 | Jan., 1990 | Veldhuis et al. | 381/41. |
4932062 | Jun., 1990 | Hamilton | 381/46. |
4972484 | Nov., 1990 | Thiele et al. | 381/37. |
5049992 | Sep., 1991 | Citta et al. | 358/140. |
5109417 | Apr., 1992 | Fielder et al. | 381/29. |
5115240 | May., 1992 | Fujiwara et al. | 341/51. |
5117228 | May., 1992 | Fuchigami et al. | 341/51. |
5134475 | Jul., 1992 | Johnston et al. | 375/133. |
5142656 | Aug., 1992 | Fielder et al. | 381/37. |
5151941 | Sep., 1992 | Nishiguchi et al. | 381/46. |
5157760 | Oct., 1992 | Akagiri | 395/2. |
5166686 | Nov., 1992 | Sugiyama | 341/155. |
5231484 | Jul., 1993 | Gonzales et al. | 358/133. |
Foreign Patent Documents | |||
0145788A1 | Jun., 1985 | EP | . |
0255111A2 | Feb., 1988 | EP | . |
0409248A2 | Jan., 1991 | EP | . |
0420745A2 | Apr., 1991 | EP | . |
0423050A1 | Apr., 1991 | EP | . |
0525809A2 | Feb., 1993 | EP | . |
Brandenburg et al., "Aspec: Adaptive Spectral Entropy Coding of High Quality Music Signals," Audio Engineering Society Preprint No. 3011 (Feb. 1991). Davidson et al., "Low Complexity Transform Coder for Satellite Link Applications" Audio Engineering Society Preprint No. 2966 (Sep. 1990). Esteban et al., "Application of Quadrature Mirror Filters To Split Band Voice Coding Schemes," Record of the 1977 ICASSP, pp. 191-195 (May 1977). Johnston, "Transform Coding of Audio Signals Using Perceptual Noise Criteria," 6 IEEE Trans. on Selected Areas in Communications, 314-323 (Feb. 1988). Rothweiler, "Polyphase Quadrature Filters-A New Subband Coding Technique," 3 Proc. 1983 ICASSP 1280-1283 (Apr. 1983). Schroeder et al., "High Quality Digital Audio Encoding with 3.0 Bits/Sample Using Adaptive Transform Coding,"Audio Engineering Society Reprint No. 2321 (Mar. 1986). Stoll et al., "Masking-Pattern Adapted Sub-Band Coding: Use of the Dynamic Bit-Rate Margin," Audio Engineering Society Preprint No. 2585 (Mar. 1988). Thiele et al., "Low Bit-Rate Coding of High-Quality Audio Signals - An Introduction to MASCAM System,"230 EBU Technical Review 71-93 (Aug. 1988). Y. Mahieux & J. P. Petit, "Transform Coding of Audio Signals at 64 kbit/s," Globecom 90, vol. 1, pp. 518-522 (Dec. 1990). |